MUSINGS ON SCIENCE & SOCIETY

A recent paper published in Proceedings of National Academy of Sciences has created quite a buzz in the media. The paper –Genome-wide data substantiate Holocene gene flow from India to Australia, from Prof. Mark Stoneking, a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, is definitely a game-changer as it challenges the long held theories about Australia’s isolation from the rest of world. A commonly held supposition is that Australia had no contact with the rest of the world between the arrival of the first humans around 45,000 years ago and the coming of Europeans in the eighteenth century.

This new paper is a result of a detailed genetic analyses which shows a couple of things:

Evidence for an ancient association between Australia, New Guinea, and the Mamanwa (a Negrito group from the Philippines), with divergence times for these groups estimated at 36,000 years ago, and hence supports the view that these populations represent the descendants of an early “southern route” migration out of Africa, whereas other populations in the region arrived later by a separate dispersal.

Further evidence pointed out that a substantial gene flow between the Indian populations and Australia happened well before European contact. The authors put this to be ~4000 years ago.

This study is one of the firsts to take a look at the genetics of Australian aboriginals and hence quite unique. The migration of Indians to Australia at ~4000 years ago, also suggests that certain tool technologies, food processing techniques, and the ancestors of dingo may be related to the migration as they only appear at this age in the Australian archaeological records.

The signal of Indian gene flow might not necessarily come directly from India. it is easy to envision a scenario whereby the Indian ancestry comes to Australia indirectly, e.g., via contact with island SE Asian populations. Indeed, it is known that some pre-European trade existed between the northeastern coast of Australia and Indonesia, but as the samples which they analysed also included some from SE Asia, and the failure to find an association with them negates this theory of SE Asian migration.

Though the study used SNP (single nucleotide polymorphisms) data from many populations in the Northern Australian territories, it however is NOTa representation of all the aboriginal populations in Australia. Hence, a much more detailed study which a larger sample set needs to be done to understand this complex history of migration.